1. Field of the Invention
The invention is concerned with hydroxyl-containing unsaturated esters or the borated derivatives thereof, that have been reacted with a mercaptothiadiazole. It also relates to lubricant compositions containing same.
2. Discussion of the Prior Art
Efforts to reduce the amount of fuel consumed by lubricated equipment and the like have accelerated in recent years having been given added impetus by the oil embargo. Many of the solutions have been strictly mechanical, but other efforts have revolved around finding lubricants that reduce the overall friction in the lubricated equipment, thus allowing a reduction in energy requirements thereto. Much work has been done with mineral lubricating oils and greases, modifying them with additives to reduce their friction properties. On the other hand, new lubricants have been synthesized and compounded for use in modern engines. Among these are the synthetic lubricating oils, which are known to reduce fuel consumption by a significant amount.
So far as is known, no effort has been made to employ the mercaptothiadiazole adducts of hydroxyl-containing acid esters or borated hydroxyl-containing esters as a lubricant additive. U.S. Pat. No. 2,788,326 discloses some of the starting esters suitable for the present invention, e.g. glycerol monooleate, as minor components of lubricating oil compositions. U.S. Pat. No. 3,235,498 discloses, among others, the same ester as just mentioned, as an additive to other oils. U.S. Pat. No. 2,443,578 teaches esters wherein the free hydroxyl is found in the acid portion, as for example in tartaric acid.
Other patents, such as U.S. Pat. Nos. 2,798,083; 2,820,014; 3,115,519; 3,282,971; and 3,309,318, as well as an article by R. S. Barnes et al, entitled "Synthetic Ester Lubricants" in Lubrication Engineering, Aug., 1957, pp. 454-457, teach lubricants prepared from polyhydric alcohols and acid containing no hydroxyl other than those associated with the acid function. However, all these references teach lubricants prepared from the fully esterified material.